1. Field of the Invention
The invention relates to a beamforming training method for concurrently beamforming training one or more communications devices in a communications system.
2. Description of the Related Art
Beamforming techniques that use multiple antennas at both the transmitter and receiver ends may be applied in a communications system to improve communications performance. Generally, the communications devices employing multiple antennas need to be trained in order to obtain optimum Tx and/or Rx antenna configurations before data transmission. For a conventional beamforming training procedure, a communications device transmits one or more predetermined beamforming training bit-sequences to a peer communications device. Then, the peer communications device receives at least one of the predetermined beamforming training bit-sequences and evaluates the channel characteristics by using the received bit-sequence(s), then returns the evaluation result to the communications device that transmitted the predetermined bit-sequences. However, the conventional beamforming training procedure is a one-to-one training procedure. Particularly, for high frequency applications, such as a millimeter wave communications system, only one communications device is preferable to be trained in a training session due to antenna directionality.
Based on the conventional beamforming training method, when there are more than one communications device in a communications system, a great number, which amount to the square of the number of the communications devices, of sessions and messages are required for the training procedure, which seriously degrades training efficiency. Thus, a novel beamforming training method that is able to solve the foregoing inefficiencies is highly required.